On September 30, European energy markets are taking the decisive step towards a new stage of integration: the introduction of 15-minute trading intervals (Market Time Units – MTU) in the Single Day-Ahead Coupling (SDAC). The first day of delivery will be October 1, 2025, marking the end of trading on a full hourly basis and the start of a much more flexible approach, closer to technological and consumer realities.

Europe adopts 15-minute market interval for next-day trading

The decision comes after more than a year-long testing campaign, conducted at local, regional and cross-border level, in which Designated Electricity Market Operators (NEMOs) and Transmission System Operators (TSOs) validated the technical functionality and connectivity of the systems. Two stages dedicated to the participants also allowed them to verify the readiness of their own IT platforms and integration capacity.

OPCOM has officially confirmed the launch of the 15-minute products on the energy market for the next day, synchronizing with the whole SDAC mechanism. For Romania, this is not just a technical first, but a proof of maturity and integration into the single European market.

“The preparations have been successfully completed and the test results confirm that the systems are fully ready for the launch of the 15-minute interval,” OPCOM reports. The operator also acknowledges the active contribution of market participants to this modernization effort, stressing that the success of the implementation depends on the coordinated involvement of all players – from transmission operators to traders and producers.

Relevance and impact

The introduction of 15-minute granularity will have visible effects on all actors in the energy ecosystem.

• Producers, especially renewables, will be better able to capitalize on the availability of intermittent resources. Rapidly fluctuating solar and wind power will be more accurately integrated into the market, reducing imbalances and penalties associated with deviations from forecasts.
• Suppliers and traders will benefit from greater finesse in portfolio management, with the possibility to calibrate purchases and sales according to actual consumption developments. This flexibility could increase competition and liquidity, but will require additional investment in forecasting systems, IT and optimization algorithms.
• The transmission and system operator – Transelectrica – will have more appropriate tools at its disposal for balancing the grid, which translates into a more efficient use of resources and a reduction in the costs of system services. At the same time, Romania’s integration into the European SDAC mechanism in the 15-minute format will facilitate cross-border exchanges and more efficient use of interconnections.
• Large (industrial) consumers will be the main indirect beneficiaries. Through a more competitive market, better adapted to technological realities, they will have access to fairer prices and increased opportunities for consumption management, including demand-response solutions.

The European premiere on September 30 is not just a technical adjustment, but a paradigm shift. The 15-minute granularity is the foundation for a more transparent, competitive and flexible market, capable of responding to the energy transition and the need to integrate renewables.

For Romania, this step confirms full synchronization with the European dynamics and is a chance to better exploit renewable resources and regional interconnections. At the same time, the change raises the stakes for all market players: adapting quickly to the new (digital) tools will make the difference between those who gain from flexibility and those who remain stuck in the rigidity of past practices.